Watching a video entitled Airbus A330 Takeoff Sidestick View, there appears to be a lot of side-to-side movement of the sidestick, as well as a lot of pushing the nose down:

I was under the impression that movements on the control column should be smooth and not erratic — what is the reason for the side-to-side movement? As far as I can see on the MFDs, there is no heading change prior to 02:50 (which appears to be done by the A/P anyway). Is it turbulence?

Also, what is the reason for pushing the nose down? Is the plane naturally trying to pull up at too high of an angle?

This landing video appears to show even more erratic control. Is this normal?

2 Answers
2

One of the unique aspects of Airbus fly-by-wire aircraft is that the sidesticks provide NO feedback. Because of this, the planes have an automatic trim system. Once the aircraft is pitched to a desired attitude, the pilot will then release the control stick and the aircraft will continue to fly at the selected attitude.

Correspondingly, if a pilot desires to reduce the pitch, they must push the stick forward to do so. In an Airbus (unlike most other aircraft), a pilot doesn't manipulate trim at all (except in non-normal situations).

As an aside, in the normal flight regime, Airbuses provide automatic protections from unsafe attitudes. Thus, if a pilot desires maximum rate of climb (that is possible in the current configuration), he can simply pull the sidestick all the way back. The computer will automatically keep the aircraft from exceeding maximum load factor and/or critical angle-of-attack.

To answer the other part of your question, the lateral stick movement is likely due to turbulence. Control inputs in large aircraft tend to be more pronounced than smaller aircraft (due to slower aircraft reaction times).

$\begingroup$Hmm.. I think alpha floor and alpha max are both related to stalling, not overspeed. Also, maximum rate of climb is not necessarily at the highest angle of attack.$\endgroup$
– falstroApr 18 '14 at 13:51

1

$\begingroup$Oops, you're right! That's what I get for writing answers late at night. Alpha protections are specific to stall prevention. I've revised my answer to remove the incorrect information.$\endgroup$
– newmanthApr 18 '14 at 14:03

For each takeoff in a jet like this, there is a target airspeed that is used during the climb just after takeoff. When the nose of the aircraft is first lifted, a target pitch setting is used which should get close to that airspeed. After things start to stabilize, corrections are made to the pitch in order to capture and maintain the desired airspeed.

Pay close attention to the Primary Flight Display during the takeoff:

You will see that the pilot is simply making corrections in order to maintain the desired airspeed and bank angle:

For pitch control (forward and aft stick movement) he is correcting to maintain the airspeed. If you watch the video carefully, you will notice that each time that the trend vector on the left side of the airspeed line moves up (indicating that the airplane will increase in speed if no changes are made), the pilot pulls back on the stick (and vice-versa) in order to maintain the airspeed. It looks to me like he is pulling back just as much as pushing forward for most of the initial takeoff, until he starts accelerating just before the 3:00 mark.

For bank control (left and right stick movement) he is correcting to maintain wings level until he starts the turn just before the 3:00 mark. Watch the yellow triangles at the top of the blue part of the attitude indicator, and you will see that if they don't match up (like in the picture above) that he makes a correction with the stick to line them back up again.

This particular flight must have had turbulence because both the bank and the airspeed were jumping around a fair amount, requiring constant adjustments on the part of the pilot.